Invasive Species Management

clickable image for COVID closure info Opens in new windowEffective March 16, 2020, Jefferson County offices are closed to the public. Many offices will be providing services online. Please contact individual offices to learn more and visit the COVID Closure page for countywide closure information. 

Need noxious weed advice?

We are working remotely but are monitoring calls and questions. See our contact information on the right-hand side of this page.

Protecting natural resources

The Jefferson County Invasive Species Management program helps protect natural resources through education and outreach.  We assist the public by developing integrated management plans to control forest insect pests and noxious weeds. The program coordinates with private entities and local, state, and federal governmental agencies to achieve regional pest control.

This site includes information to help identify, control and prevent forest pests and noxious weed infestations. Our goal is to educate the public about weed and pest problems and offer solutions.


Land Stewardship Series

Information about upcoming programs

UPDATE: Due to emerging COVID-19 issues, we are going to cancel this public event this month. 


2020 Noxious Weed Awareness Campaign - April

Leafy spurge

Euphorbia escula

Leafy spurge is a perennial member of the spurge family.  This List B noxious weed reproduces by seed and spreading roots.  Seeds are expelled up to 15 feet from ripened seed pods and have a sticky gel-like substance on their surface that allows seeds to stick onto wildlife, pets, humans, and equipment.  Roots grow horizontally to 15 feet and vertically to 30 feet.  Plants can grow from root fragments as small as 1/8-1/4 inch long.  Roots have growth buds along their length that give rise to new plants.

Leafy spurge flowers from May through July.  The flower parts are inconspicuous and are found in the middle of modified bracts that are bright yellowish green.  These form clusters at the ends of stems.

Leaves are narrow, about 1-4 inches long, with smooth surfaces and edges.

Plants grow to about 3 feet tall.  Stems are thin.  Plants have a milky latex sap that can be toxic.  It can cause blistering on the lips of livestock.  Plants may appear reddish in the fall.

In some areas of Colorado Leafy spurge populations have declined significantly, in part due to biological control beetles. Visit CDA’s Insectary website for more info.

Leafy spurge is a problem in rangeland, pastures, parklands and riparian corridors.

Control includes good land management, biological control, and chemical.  Mowing or grazing with goats combined with other methods has shown results in some areas.

What You Can Do

  • Choose weed-free hay when feeding hay to livestock
  • Survey your property in early spring to identify patches of leafy spurge so you can control it before it seeds
  • Do not walk or drive through patches of leafy spurge


Team Leafy Spurge


CSU Extension Fact Sheet

CDA Factsheet  

hoary cress seedpod

2020 Noxious Weed Awareness Campaign - March

Hoary Cress

Cardaria draba

Other Names: Whitetop, Heart-podded whitetop

Hoary cress is a List B perennial. This member of the mustard family reproduces by seed and rhizomes and can quickly form a monoculture.

Plants can be up to about 18 to 24 inches tall but are generally smaller. The leaves are dark green. Lower leaves have a petiole but leaves higher on the plant clasp the stem. Dense clusters of four-petaled white flowers grow at the ends of upright branches. Seedpods are slightly inflated and heart-shaped. Each plant produces up to 4800 seeds per year.

Large patches can be seen along roadsides and in parks in early spring. Hoary cress is also an agricultural pest in rangeland, pastures and in crops such as wheat.

Hoary cress has been known in Colorado since 1898. There are also two other weedy whitetops known in the state. Lens-podded whitetop (Cardaria chalapensis) and Hairy whitetop (Cardaria pubescens).

What You Can Do

Talk to your local park manager and see if they would like help locating patches of noxious weeds.

If you have Hoary cress on your property, treat it before it blooms.

Tell your neighbors. We will all benefit when more people become aware of the problem and take action.


Clean your gear and equipment when moving between different sites. Whether you are a hiker, biker or work outdoors, weeds can easily be moved unintentionally by clinging to your clothing and equipment. Learn more at PlayCleanGo


Field Guide for Managing Whitetop in the Southwest

Weed Control in Natural Areas in the Western United States

CWMA Factsheet

CDA Factsheet

NEW - Colorado’s Noxious Weed Awareness Campaign

2020 marks the 30th anniversary of the Noxious Weed Law. Jeffco Invasive Species Management is a partner in COLORADO’s NOXIOUS WEED AWARENESS CAMPAIGN.  See a sneak peak of our first video HERE



Jefferson County Open Space will be applying herbicides at the following parks:

Week of 4/5/2020

Clear Creek Canyon
Windy Saddle Park